Removing broken bolts

[wheels]

I have to remove a couple of motor mounts in a block(not a slick)and I know getting a hole center and straight is hard. I was told to do this 1. if there is any thread in the hole cut the thread off of a bolt that threads in the hole
2. Take that piece of bolt to the drill press and drill the proper size hole thru it for your easy out.
3. Take the drilled piece and thread it in as far as possible and use it as a bushing for a straight and center hole.
Has anyone tried this it sounds like it might work.

[jamesdfo]

If you are fortunate enough to have the bolt break off way below flush, that should work well.....I have never been that fortunate:)
A good friend of mine used to have his own exhaust shop, and more than once, I watched him take a nut, place it over the broken off (flush or below flush) exhaust stud on a cyllinder head, and mig through the center of the nut.....then let it cool and crank it out with a socket....but again, it never worked for me when I tried it.....some guys have "the touch", some don't....

James

[Toyz]

Different situations merit different approaches. Jame's suggestion works well. If you don't have a welder or easy access to the location, a coupling nut and a flat washer (thin) can be your friend.If there is enough of the broken piece exposed, thread the coupling nut in place, and drill out with the tap sized drill. A left hand cobalt bit can prove very handy for this, and often will back out the stud completely. If none of the broken piece is exposed, refer to Wheel's suggestion.If there is very little exposed, clean the exposed surface with a wire brush or similiar, chase the coupling nut with a tap and degreaser, apply a slight amount of anti-seize to the lower side of the flat washer, put a small amount of Belzona (JB Weld may work), inside the contact end of the coupling nut with a Q-tip, etc, put it in place and thread it out. If it breaks loose at the coupling nut, repeat the procedure; the contact area will probably be improved the second time.
Satisfaction (almost) guaranteed after 50-60 tries!
Paul

[BMJ's 65]

I deal with alot of broken bolts and such here in the tool room. I've found that a sharp center punch mark, eyeballed in the middle of the broken bolt is the best place to start. Follow that up using a center drill (combination drill counter sink in the MSC catalog) and then move on to the left handed drill bit as Toyz stated below. many times the broken piece will back out with the left handed drill. If the chunk does not come out, I like to step up in drill sizes and get as close to the tap drill size for the bolt as I can. Once the body of the broken bolt has been removed, the threads can be chased woth a tap to remove whats left of the origional threads of the bolt.

[Uncle Skip]

All of the above. If you can find a flat ended mill cutter the size of your opening, you can flatten the broken end of the bolt and then center punch it so the drill bit will go in straight. I've used the Dremel tool abrasive cylinder the size of the threaded opening (with a flat end) for that. After I center punch the bolt, I always start with the smallest bit I have.... in my case, a #40 and open things up from there. Bigger is better if you don't get into the threads on the sides of the hole. Also, when you get ready to use the easy out, put heat on the broken bolt area with a hand held propane torch first.
Just don't force things and break the easy out. Trust me.

[64 f100]

I've found that the appropriate choice of words will often shame the bolt into coming out. Just remmember, if you get frustrated, walk away ukntill the next day , if you can let it go often your mind and freinds will give you the apropriate action to take. Just sleeping on it does wonders, as your mind will make decisions while you rest. Removing bolts is also a matter of whether it broke going in or coming out. A rusty bolt that hasn't moved coming out means it's rusted in the hole and more of a problem. Main thing to remmember is get you hole dirlled straight to start with. Use a smaller pilot drill bit and don't force it or God help you, break off the bit in the hole. Major problem then. Once you can get any easy out in it, You still have a stuck bolt. I suggest generous amounts of PB blaster or some other product similar in design and let it set for awhile then spray it again just before trying to remove it. NOT WD40! The other suggestions are good and often work, partly because the heat from welding really helps.

Rich